MGSLG. (2020). Module 5 Unit 2

What is a negative feedback mechanism?

Homeostasis

It is a process of maintaining a constant internal environment (blood and tissue fluid) within the body. This enables the body to function efficiently, despite changes in the external or internal environment.

The following changes of the internal environment in the tissue fluid and blood, will affect the homeostatic balance of the body:

  • temperature
  • glucose levels
  • carbon dioxide levels
  • water levels and salt levels


NEGATIVE FEEDBACK MECHANISMS

They operate in the human body to detect changes or imbalances in the internal environment and to restore the balance.

General sequence of events in a negative feedback mechanism:

  • STEP 1-  An imbalance is detected
  • STEP 2 - A control centre is stimulated
  • STEP 3-  Control centre responds
  • STEP 4- Message sent to target organ/s
  • STEP 5- The target organ responds
  • STEP 6- It opposes/reverses the imbalance
  • STEP 7- Balance is restored


1: Regulation of thyroxin levels in the body:


2: Regulation of glucose levels through negative feedback mechanism



A flowchart depicting the negative feedback mechanism of glucose levels in the blood:


3: The regulation of carbon dioxide levels in the blood:


4: The regulation of water balance in the blood. Osmoregulation in the blood:



Diagram of the nephron in the kidney with distal convoluted tubule and collecting tubule:


Flow chart depicting the regulation of water in the blood (osmoregulation):


5: The regulation of salt levels in the blood stream:



Flow chart depicting the regulation of salt levels in the blood stream:




Last modified: Tuesday, 23 March 2021, 7:06 AM